For an HVLP gravity feed, Nason recommends between 1.3 and 1.6

http://pc.dupont.com/dpc/en/US/html/visitor/common/pdfs/b/product/nsn/Nason/fulbaseb-cbasecoat.pdf


For the clear, Dupont has quite a few different lines. Do a google on "Dupont XX clear coat tech sheet" (fill in the x's with the pn) and you should get a tech sheet like the one linked above that will give you that info.

I think you'd need a 1.3 to a 1.4, but see what the clear calls for first..